Computer-aided techniques are increasingly being used to capture, identify, validate, and extract information from security documents. For example, security document readers, such as ePassport readers, are more commonly being deployed to read and confirm the authenticity of security documents. Examples of security documents include passports, credit cards, ID cards, driver's licenses, birth certificates, commercial papers, and financial documents. For some security documents, the ICAO (International Civic Aviation Organization) provides a clear procedure for identifying security documents with computer-aided techniques. For other security documents, no standards exist that specify procedures by which a computer-aided technique may identify non ICAO-compliant security documents.
In general, before the authenticity of a given security document can be confirmed, the type of security document must first be identified. For example, some modern security document readers support a variety of different types of security documents, such as passports issued by various states or countries. In order to confirm that a security document is an authentic passport, for example, it must first be determined which specific country and version of passport is being authenticated. Authentication of a British passport may require application of different algorithms and/or analysis of different portions of the passport than, for example, an Australian passport. More specifically, in order to authenticate different security documents, a security document reader may employ a wide variety of algorithms, including those analyzing document sizes, static image patterns, and/or information collected from specific positions on the document and/or storage mediums, e.g., bar codes, machine-readable zones, and RFID chips.
The process of first identifying the type of security document may present a significant challenge for non ICAO-compliant documents. One approach is to require an operator to manually select the type of security document prior to processing the document to confirm its authenticity. This approach, however, can be manually intensive and prone to error in environments that processes high volumes of security documents.
Alternatively, certain computer-aided techniques may be applied in an attempt to automatically or semi-automatically identify the type of security document. However, to date, such techniques are typically static in nature (i.e., rigidly defined). That is, a document authentication system may be statically programmed to apply a first algorithm to test for a first type of security document. If the test fails, the document authentication system applies a second algorithm to test for second type of security document. This static process continues in sequence until the security document is either identified or rejected. The rigid nature and significant processing time required by this static approach is not well-suited for document authentication systems designed to support a large number of different document types, and may limit the scalability of such a system.